//
// SHA1Engine.h
//
// Library: Foundation
// Package: Crypt
// Module:  SHA1Engine
//
// Definition of class SHA1Engine.
//
// Secure Hash Standard SHA-1 algorithm
// (FIPS 180-1, see http://www.itl.nist.gov/fipspubs/fip180-1.htm)
//
// Based on the public domain implementation by Peter C. Gutmann
// on 2 Sep 1992, modified by Carl Ellison to be SHA-1.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef Foundation_SHA1Engine_INCLUDED
#define Foundation_SHA1Engine_INCLUDED


#include "Poco/DigestEngine.h"
#include "Poco/Foundation.h"


namespace Poco
{


class Foundation_API SHA1Engine : public DigestEngine
/// This class implements the SHA-1 message digest algorithm.
/// (FIPS 180-1, see http://www.itl.nist.gov/fipspubs/fip180-1.htm)
{
public:
    enum
    {
        BLOCK_SIZE = 64,
        DIGEST_SIZE = 20
    };

    SHA1Engine();
    ~SHA1Engine();

    std::size_t digestLength() const;
    void reset();
    const DigestEngine::Digest & digest();

protected:
    void updateImpl(const void * data, std::size_t length);

private:
    void transform();
    static void byteReverse(UInt32 * buffer, int byteCount);

    typedef UInt8 BYTE;

    struct Context
    {
        UInt32 digest[5]; // Message digest
        UInt32 countLo; // 64-bit bit count
        UInt32 countHi;
        UInt32 data[16]; // SHA data buffer
        UInt32 slop; // # of bytes saved in data[]
    };

    Context _context;
    DigestEngine::Digest _digest;

    SHA1Engine(const SHA1Engine &);
    SHA1Engine & operator=(const SHA1Engine &);
};


} // namespace Poco


#endif // Foundation_SHA1Engine_INCLUDED
